include/linux/completion.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef __LINUX_COMPLETION_H
   3 #define __LINUX_COMPLETION_H
   4
   5 /*
   6  * (C) Copyright 2001 Linus Torvalds
   7  *
   8  * Atomic wait-for-completion handler data structures.
   9  * See kernel/sched/completion.c for details.
  10  */
  11
  12 #include <linux/wait.h>
  13 #ifdef CONFIG_LOCKDEP_COMPLETIONS
  14 #include <linux/lockdep.h>
  15 #endif
  16
  17 /*
  18  * struct completion - structure used to maintain state for a "completion"
  19  *
  20  * This is the opaque structure used to maintain the state for a "completion".
  21  * Completions currently use a FIFO to queue threads that have to wait for
  22  * the "completion" event.
  23  *
  24  * See also:  complete(), wait_for_completion() (and friends _timeout,
  25  * _interruptible, _interruptible_timeout, and _killable), init_completion(),
  26  * reinit_completion(), and macros DECLARE_COMPLETION(),
  27  * DECLARE_COMPLETION_ONSTACK().
  28  */
  29 struct completion {
  30         unsigned int done;
  31         wait_queue_head_t wait;
  32 #ifdef CONFIG_LOCKDEP_COMPLETIONS
  33         struct lockdep_map_cross map;
  34 #endif
  35 };
  36
  37 #ifdef CONFIG_LOCKDEP_COMPLETIONS
  38 static inline void complete_acquire(struct completion *x)
  39 {
  40         lock_acquire_exclusive((struct lockdep_map *)&x->map, 0, 0, NULL, _RET_IP_);
  41 }
  42
  43 static inline void complete_release(struct completion *x)
  44 {
  45         lock_release((struct lockdep_map *)&x->map, 0, _RET_IP_);
  46 }
  47
  48 static inline void complete_release_commit(struct completion *x)
  49 {
  50         lock_commit_crosslock((struct lockdep_map *)&x->map);
  51 }
  52
  53 #define init_completion(x)                                              \
  54 do {                                                                    \
  55         static struct lock_class_key __key;                             \
  56         lockdep_init_map_crosslock((struct lockdep_map *)&(x)->map,     \
  57                         "(complete)" #x,                                \
  58                         &__key, 0);                                     \
  59         __init_completion(x);                                           \
  60 } while (0)
  61 #else
  62 #define init_completion(x) __init_completion(x)
  63 static inline void complete_acquire(struct completion *x) {}
  64 static inline void complete_release(struct completion *x) {}
  65 static inline void complete_release_commit(struct completion *x) {}
  66 #endif
  67
  68 #ifdef CONFIG_LOCKDEP_COMPLETIONS
  69 #define COMPLETION_INITIALIZER(work) \
  70         { 0, __WAIT_QUEUE_HEAD_INITIALIZER((work).wait), \
  71         STATIC_CROSS_LOCKDEP_MAP_INIT("(complete)" #work, &(work)) }
  72 #else
  73 #define COMPLETION_INITIALIZER(work) \
  74         { 0, __WAIT_QUEUE_HEAD_INITIALIZER((work).wait) }
  75 #endif
  76
  77 #define COMPLETION_INITIALIZER_ONSTACK(work) \
  78         (*({ init_completion(&work); &work; }))
  79
  80 /**
  81  * DECLARE_COMPLETION - declare and initialize a completion structure
  82  * @work:  identifier for the completion structure
  83  *
  84  * This macro declares and initializes a completion structure. Generally used
  85  * for static declarations. You should use the _ONSTACK variant for automatic
  86  * variables.
  87  */
  88 #define DECLARE_COMPLETION(work) \
  89         struct completion work = COMPLETION_INITIALIZER(work)
  90
  91 /*
  92  * Lockdep needs to run a non-constant initializer for on-stack
  93  * completions - so we use the _ONSTACK() variant for those that
  94  * are on the kernel stack:
  95  */
  96 /**
  97  * DECLARE_COMPLETION_ONSTACK - declare and initialize a completion structure
  98  * @work:  identifier for the completion structure
  99  *
 100  * This macro declares and initializes a completion structure on the kernel
 101  * stack.
 102  */
 103 #ifdef CONFIG_LOCKDEP
 104 # define DECLARE_COMPLETION_ONSTACK(work) \
 105         struct completion work = COMPLETION_INITIALIZER_ONSTACK(work)
 106 #else
 107 # define DECLARE_COMPLETION_ONSTACK(work) DECLARE_COMPLETION(work)
 108 #endif
 109
 110 /**
 111  * init_completion - Initialize a dynamically allocated completion
 112  * @x:  pointer to completion structure that is to be initialized
 113  *
 114  * This inline function will initialize a dynamically created completion
 115  * structure.
 116  */
 117 static inline void __init_completion(struct completion *x)
 118 {
 119         x->done = 0;
 120         init_waitqueue_head(&x->wait);
 121 }
 122
 123 /**
 124  * reinit_completion - reinitialize a completion structure
 125  * @x:  pointer to completion structure that is to be reinitialized
 126  *
 127  * This inline function should be used to reinitialize a completion structure so it can
 128  * be reused. This is especially important after complete_all() is used.
 129  */
 130 static inline void reinit_completion(struct completion *x)
 131 {
 132         x->done = 0;
 133 }
 134
 135 extern void wait_for_completion(struct completion *);
 136 extern void wait_for_completion_io(struct completion *);
 137 extern int wait_for_completion_interruptible(struct completion *x);
 138 extern int wait_for_completion_killable(struct completion *x);
 139 extern unsigned long wait_for_completion_timeout(struct completion *x,
 140                                                    unsigned long timeout);
 141 extern unsigned long wait_for_completion_io_timeout(struct completion *x,
 142                                                     unsigned long timeout);
 143 extern long wait_for_completion_interruptible_timeout(
 144         struct completion *x, unsigned long timeout);
 145 extern long wait_for_completion_killable_timeout(
 146         struct completion *x, unsigned long timeout);
 147 extern bool try_wait_for_completion(struct completion *x);
 148 extern bool completion_done(struct completion *x);
 149
 150 extern void complete(struct completion *);
 151 extern void complete_all(struct completion *);
 152
 153 #endif